TAMPA — When the Tampa Bay Buccaneers selected running back Mike James in the sixth round of the 2013 draft, they did so with the belief that, in a pinch, he could step in and play right away.

Well, the Bucs are suddenly in a pinch.

The left shoulder injury lead runner Doug Martin sustained during the Bucs’ 31-23 loss at Atlanta on Sunday might not end Martin’s season, but it likely will keep him out of Thursday’s game against Carolina.

The injury is such that he could play as early as Thursday, the Bucs said, but it might require Martin to play in a lot of pain and with limited mobility in his left arm.

“It’s probably going to be a stretch for (him to play) this Thursday, although we will have to see on that,’’ head coach Greg Schiano said Monday. “I wouldn’t go any further than that right now, because I hate to put limitations on people.

“The thing is, there are different ways to handle that injury and I think we just have to wait and see how it responds to treatment. You don’t know until you try.’’

There’s a good chance safety Dashon Goldson will be available to play Thursday. Goldson suffered a knee injury against the Falcons, but Schiano expressed some optimism about his availability, saying he is “truly day to day.’’

Martin was hurt early in the third quarter when he took a hit from William Moore while attempting to catch a deep pass from Mike Glennon near the goal line.

Martin said after the game he was not in a lot of pain and that he had some range of motion in his left shoulder, but would need to undergo further testing to learn the injury’s severity. Those tests took place Monday.

Several Internet reports early Monday, citing unnamed sources, said Martin suffered a torn labrum that would end his season, but the Bucs refused to confirm those reports and Schiano was not specific about the injury.

Tampa Bay is not ready to call an end to Martin’s season just yet.

“If it were season ending I would let you know, but I don’t feel that it is right now,’’ Schiano said. “We, our medical team, doesn’t feel that it is. So, we’re just going to play it by ear and go from there.’’

A 2012 first-round draft pick out of Boise State who made the Pro Bowl as a rookie after accumulating 1,926 total yards from scrimmage last year, Martin was unavailable for comment Monday.

He is coming off one his better games of the year, one in which he ran 11 times for 47 yards (4.3 yards per carry) and gave way to James after leaving the game with the injury.

James, who carried the ball just three times prior to Sunday, ran 14 times for 45 yards (3.2 yards per carry) against the Falcons, including once for 11 yards. His biggest contribution, though, might have come as a pass protector.

On first-and-10 from the Tampa Bay 41-yard line, James stepped in front of blitzing cornerback Desmond Trufant and impeded his progress enough to allow Glennon to get off a deep pass that resulted in a 59-yard touchdown to Vincent Jackson.

“That was about as good as (you’ll see),’’ Schiano said of James’ blitz pickup. “That guy was coming with a full head of steam and Mike, as they say, got run over slowly. But he allowed us to get that play off.’’

The question now is will James allow the Bucs to run the ball effectively. They’ve struggled in that area this year, averaging 101.2 yards per game, which ranks 20th in the league, and 3.8 yards per carry, which is 23rd in the league.

Those figures aren’t likely to improve much with a mostly untested rookie in the lineup, but Schiano has seen some things from James that make him think he will be a viable weapon.

“When he’s had his opportunities he’s done good things,’’ Schiano said. “He’s got really good one-cut ability as far as when things flash in front of his face in the backfield or at the line of scrimmage, and he’s got some quick feet. He can make that first guy miss, so he keeps you out of negative plays, which is big. And he seems to fall forward a lot, which is an important thing for a running back.”

The Bucs won’t lean solely on James if Martin is out. They also will make use of veteran Brian Leonard and on Monday claimed second-year pro Bobby Rainey off waivers from the Cleveland Browns.

For this week, though, the opportunity to step in for Martin will almost certainly go to James, a Davenport native who played at the University of Miami and is no stranger to big games and bright lights.

“I understand the circumstances, but I pressure myself more than anybody,” James said. “And I feel like I understand (the offense) and have a good feel for everything and will be ready.

“Doug’s a great running back, a Pro Bowl running back, so there’s a lot of pressure just trying to fill half his shoes. All I can do is go out there and do what I have to to help us win the game.’’